Determination of minute traces of water by use of methylene blue



iinited States Patent W DETERMINATION OF MINUTE TRACES (3F WATER BY USEOF METHYL-ENE BLUE Florence Nesh, 164 Hart St., Brooklyn 6, NY. NoDrawing. Filed Sept. 24, 1956, Ser. No. 511,796

4 Claims. (Cl. 23-230) (Granted under Title 35, US. Code (1952), sec.266) The invention described herein may be manufactured and used by orfor the Government of the United States of America for governmentalpurposes without the payment of any royalties thereon or therefor.

The present invention concerns a composition and method fordetermination of minute traces of water in materials that contain nowater molecules or potential water molecules as a basic part of itsstructure. In particular the invention relates to a composition andmethod for determination of minute traces of water in materials such asjet fuel by use of an indicator such as methylene blue.

An object of the invention is to provide a simple and sensitivecomposition and method for determination of minute traces of water inmaterials in cases where drying methods cannot be used.

Another object is to provide a composition and method for determinationof minute traces of water in material such as jet fuel by use of anindicator such as methylene blue.

Another object is to provide an indicator composition for detectingminute traces of water in a methylene blue inert material such as jetfuel in which the composition comprises a methylene-blue-inert solventthat forms a solution in which the water is less soluble than in thematerial alone, and the composition further comprises an admixture ofmethylene blue.

Another object is to provide a method for determination of minute tracesof water in a methylene-blue-inert material such as jet fuel whichcomprises releasing the water by dissolving a sample of the material ina methylene-blue-inert solvent to form a solution in which the water hasdecreased solubility and whereby the water coagulates in globules, andthen exposing the released water to methylene blue indicator.

Other objects and many of the attendant advantages of this inventionwill be readily appreciated as the same becomes better understood byreference to the following detailed description.

The determination of minute traces of water, especially in cases wheredrying methods cannot be used, has been :difiicult in the past and hasinvolved the use of long procedures and complicated and unwieldlyapparatus. These difiiculties are overcome by the present inventionwhich provides a simple and very sensitive composition and method makinguse of an indicator such as methylene blue that has extreme solubilityin water.

The determination may be made, for example, by dissolving one volume ofsample material such as jet fuel in two volumes of solvent such ascarbon tetrachloride and a small quantity of methylene blue. Waterpresent Patented Aug. 30, 1960 materials. A preferable solvent with jetfuel and hexachlorethane is carbon tetrachloride, although othersolvents such as acetone and benzol can be used provided that they donot react with the indicator being used and they do not react with thematerial being tested and furthermore that with jet fuels andhexachlorethane they form a solution with the material in which thewater is less soluble than it is with the material alone. The indicatorused is preferably methylene blue because of its extreme solubility inwater and because of the fact that it does not react on materials suchas jet fuel and hexachlorethane and furthermore it does not react withsolvents such as carbon tetrachloride, acetone 'and benzol. Indicatorsother than methylene blue can be used so long as they are extremelysoluble in water and have a high sensitivity thereto, and provided thatthey furthermore do not react with the material being tested and do notreact with the solvent used.

In application of the invention to materials such as petroleums andhexachlorethane a determination is made by dissolving a sample of thematerial to be tested in a suitable solvent and adding the indicator.For example jet fuel is dissolved in carbon tetrachloride and methyleneblue is added. Water present in the sample tends to be released due todecreased solubility of the water in the mixture of jet fuel with carbontetrachloride. Upon release the water coagulates in globules. If theindicator is methylene blue, it is a dry, water soluble, reddish-brownpowder in the carbon tetrachloride before formation of water globulesand it turns a deep blue upon formation of the globules thus indicatingthe presence of water.

Example 1 One volume of jet fuel, Navy Grade IP-S or heavy end fuel HEAFis dissolved in two volumes of carbon tetrachloride and a small quantitysuch as 10 mg. of dry methylene blue, water soluble, technical, FisherCat. No. A-766 is added. Water present in the sample tends to bereleased due to decreased solubility in the mixture of jet :fuel andcarbon tetrachloride and the water coalesces in globules. The methyleneblue which remains as a reddish-brown powder in the carbon tetrachloridewill turn a deep blue as globules form indicating the presence of water.The saturation point of the jet fuel used in this example had beencarefully studied and determined to be about at 0.011% water. Variousvolumes of this water-saturated jet fuel were dissolved in carbontetrachloride and methylene blue added. As little as 0.08 mg. of water,representing 0.000016% on the basis of a 500 gm. sample were indicatedby the methylene blue. The dry jet fuel when dissolved in the carbontetrachloride showed no reaction with methylene blue.

Example 2 One volume of turbine oil is dissolved in two volumes ofcarbon tetrachloride and a small quantity such as 10 mg. of drymethylene blue, water, soluble, technical, Fisher Catalogue No. A-76 6is added. Water present in the sample tends to be released due todecreased solubility in the mixture of turbine oil and carbontetrachloride and the water coagulates in globules. The methylene bluewhich remains as a reddish-brown powder in the carbon tetrachloride willturn a deep blue as globules form indicating the presence of water.Various samples of turbine oil containing different quantities of waterwere tested and as little as 0.03 mg. of water was detected. The dryturbine oil when dissolved in the carbon tetrachloride showed noreaction with the methylene blue.

Example 3 One volume of the sample of hexachlorethane which mately mg.of dry methylene blue, water soluble,

technical, Fisher Cat. No. A-766 was added. Water present in the sampletends to be released due to de creased solubility in the mixtureofhexachlorethaneand carbon tetrachloride, and coagulates in globules.-The methylene blue which remains as a reddish-brown powder in the carbontetrachloride will turn a deep blue as globules form indicating thepresence of water. This indication will appear with as little as 0.03mg. of Water.

Obviously many modifications and variations of the present invention arepossible in the light of the above teachings. the scope of the appendedclaims the invention may be practiced otherwise than as specificallydescribed.

I claim:

1. A method for determining the presence of trace amounts of water in aliquid material to be examined and that contains no water molecules andno potential water molecules as a basic part of its structure, whichcomprises adding to said material anhydrous carbon tetrachloride in aquantity sufiicient to free any water that is incorporated in saidliquid material, agitating this mixture to free any water incorporatedtherein, and then adding to the mixture a small quantity of dry, watersoluble, methylene blue,- whereby any water released from said liquidmaterial will dissolve said methylene blue and change its color to adeep blue.

2. A method for determining the presenceof trace amounts of chemicallyuncombined but physically entrapped water in a material to be examinedand that a quantity sufficient torelease any water that is physi callyentrapped in said material, and a small quantity of- It is therefore tobe understood that within dry, water soluble, methylene blue, wherebyany water released from its physical entrapment in said material willdissolve said methylene blue and change its color to blue.

3. A method for determining the presence of trace amounts of water in aliquid petroleum compound that contains no water molecules and nopotential water molecules as a basic partof its structure, whichcomprises bringing saidpetroleum into intimate contact with carbontetrachloride in an amount suflicient to free any water incorporated insaid petroleum, and a small quantity of dry, water soluble methyleneblue, whereby the water released from said petroleum by said carbontetrachloride will dissolve said methylene blue and change its color toits deep blue.

4. The method according to claim 2 wherein the contacfofthe materialwith the methylene blue occurs after the contact of the material withthe carbon tetrachloride.

References Citedin thefile of this patent i UNITED STATES PATENTS270,489

, OTHER REFERENCES Weber: Kiiltetechnik, October 1954, Iahrg. 6, pp. 267to 269.

v Allenetal.: Methods for the Determination of Water in, Petroleum andits Products, Bureau of Mines Pe-- troleum Technilogy 1, Technical Paper25 (1912), page 5.

'Ofiicial and Tentative Methods of Analysis of the Assoc. ofOfiicialAgricultural- Chemists, 6th ed. (1945), published .by the Assoc.of Official Agricultural Chemists, Washington, D. C. Sec. 39.60(a) pages683, 684.

1. A METHOD FOR DETERMINING THE PRESENCE OF TRACE AMOUNTS OF WATER IN ALIQUID MATERIAL TO BE EXAMINED AND THAT CONTAINS NO WATER MOLECULES ANDNO POTENTIAL WATER MOLECULES AS A BASIC PARTS OF ITS STRUCTURE, WHICHCOMPRISES ADDING TO SAID MATERIAL ANHYDROUS CARBON TETRACHLORIDE IN AQUANTITY SUFFICIENT TO FREE ANY WATER THAT IS INCORPORATED IN SAIDLIQUID MATERIAL, AGITATING THIS MIXTURE TO FREE ANY WATER INCORPORATEDTHEREIN, AND THEN ADDING TO THE MIXTURE A SMALL QUANTITY OF DRY, WATERSOLUBLE, METHYLENE BLUE, WHEREBY ANY WATER RELEASED FROM SAID LIQUIDMATERIAL WILL DISSOLVE SAID METHYLENE BLUE AND CHANGE ITS COLOR TO ADEEP BLUE.